The US is a rogue superpower. Its decision last week to renounce participation in the climate agreement reached in Paris in December 2015 underlined this reality. The question is how to respond.Denial of man-made global warming is an article of faith for many Republicans: Donald Trump’s hostility to action is no idiosyncrasy. But clever lobbying reinforces disbelief. The debate parallels those on the dangers of lead and tobacco. In those cases, too, lobbies exploited every uncertainty. The arguments for action on climate are quite as strong as on lead and tobacco. But obfuscation has again been effective.American views on the US role in the world also matter. HR McMaster and Gary Cohn, Mr Trump’s advisers on security and economics, have recently written that: “The president embarked on his first foreign trip with a clear-eyed outlook that the world is not a ‘global community’ but an arena where nations, non-governmental actors and businesses engage and compete for advantage. We bring to this forum unmatched military, political, economic, cultural and moral strength. Rather than deny this elemental nature of international affairs, we embrace it.” These, we must remember, are the “adults” in the White House.The US abandoned such a 19th-century view of international relations after it ended so catastrophically in the 20th. In its place came the ideas, embedded in the institutions it created and the alliances it formed, that values matter as well as interests and responsibilities, as well as benefits. Above all, the earth is not just an arena. It is our shared home. It does not belong to one nation, even such a powerful one. Looking after the planet is the moral responsibility of all.Hostility to science and a narrow view of interests laid the ground for Mr Trump’s repudiation of the Paris accord. But his speech was also a characteristic blend of falsehood and resentment.Thus, Mr Trump stated that “as of today, the United States will cease all implementation of the non-binding Paris accord and the draconian financial and economic burdens the agreement imposes on our country”. Yet a “non-binding” agreement can hardly impose draconian financial and economic burdens. Indeed, the point of the agreement was that each country should come up with its “intended nationally determined contribution”. The underlying mechanism of the Paris accord was peer pressure, aimed at achieving a shared goal. No coercion was involved.Mr Trump also argued that the agreement would have little effect on the climate. As it is, that is true. The main reason for this is that significant players — including the US — would not agree to anything more. Arguing against adhering to an agreement because it is ineffective, when one’s country’s recalcitrance helped make it so, is ludicrous.Mr Trump asserted that: “We don’t want other leaders and other countries laughing at us any more. And they won’t be. They won’t be.” That is a paranoid fantasy. The US is the second-largest global emitter of carbon dioxide. Its emissions are 50 per cent larger than the EU’s and its emissions per head are twice those of that bloc or Japan. Far from being exploited by others, as Mr Trump suggests, the US emits exorbitantly. American co-operation is not a sufficient condition for management of climate risks. But it is a necessary one. This repudiation is no laughing matter. Since the agreement is built on national commitments, the sensible path for the US would have been to stay in the process and push for far more ambitious plans all around. It could have linked its efforts to what others, notably China, were willing to do. Yet now, outside the framework, it will achieve nothing of the kind. Nor is there any real chance of negotiating another framework. The commitments should evolve. The framework will not.In the 1920s, the US repudiated the League of Nations. That led to the collapse of Europe’s post-first world war settlement. Now, it is withdrawing from a shared commitment to protect our planet. The echoes are disturbing.True, 12 US states, which generate more than a third of gross domestic product, and 187 US cities have pledged to cut their emissions by 26-28 per cent below 2005 levels, by 2025, as the country promised under Barack Obama. Yet, however desirable, that cannot replace a commitment by the US, as former treasury secretary Hank Paulson argues.

Optimists also argue that technological progress on renewables is so fast that policy decisions may not matter: economics alone will drive the needed de-carbonisation of economies. This still looks implausible. Incentives and other interventions continue to matter, particularly since investment decisions have such a long-lasting effect. The infrastructure we build today will shape energy use for decades.The remaining participants in the accord must stick to their plans. They must also commission an analysis of how to deal with free riders. Everything must be considered, even sanctions.Meanwhile, those Americans who understand what is at stake need to fight against the irrationality and defeatism that led to this. If any country has the resources to make a success of the energy transition it is theirs.The US cannot be made “great” by rejecting global responsibility and embracing coal. That is atavistic. Mr Trump’s appeal to irrationality, xenophobia and resentment is frightening. The world must struggle on, trusting that Americans will once again be touched, in Abraham Lincoln’s glorious words, by “the better angels” of their nature.

If you know the other and know yourself, you need not fear the result of a hundred battles.

Sun Tzu

We are travelers on a cosmic journey, stardust, swirling and dancing in the eddies and whirlpools of infinity. Life is eternal. We have stopped for a moment to encounter each other, to meet, to love, to share.This is a precious moment. It is a little parenthesis in eternity.